Modern diamond drill bits have cutting members mounted thereon comprised of a stud assembly. The stud assembly is a generally cylindrical solid piece of metal having a surface formed at an acute angle respective to the longitudinal centerline thereof, so that a polycrystalline diamond cutting element can be attached thereto. The other or fixed end of the stud is fitted into the face of the bit body, with the cutting element being oriented respective to the bit face and to the other cutting elements to provide various different patterns so that great efficiency in penetrating geological formations is achieved.
The polycrystalline cutting element is made in the form of a very short cylinder, or wafer, having a layer of polycrystalline diamonds on the outer face thereof. The rear face of the cutting element is permanently attached to the inclined back formed on the stud.
After a bit has been used downhole in a borehole, it eventually becomes dull because of abrasive wear against the cutting element. The cutting element of a worn bit can be removed and rotated 180.degree. about its axial centerline to thereby present an unused portion of the cutting face for engagement with a geological formation.
Difficulty has been experienced in bonding the cutting element to the inclined surface of the stud and it often is sheared or broken off. This presents a number of additional problems, all of which are expensive to overcome and substantially adds to the cost of drilling for hydrocarbons.
Accordingly, it would be desirable to have made available an improved method by which the cutting element is bonded to the inclined surface of the stud. It would furthermore be advantageous to be able to utilize only half of the wafer-like polycrystalline cutting element. It would especially be desirable if both of these improvements could be combined together to provide an unusual and novel stud assembly for use in a diamond drill bit. Such a stud assembly is the subject of the present invention.